I've tried doing  Bonus - Initiative - WIS.   Then i tried adding my modifier as a fixed value (3). Still doesn't work.

Modifier: Bonus->Subtype: Initiative->Ability Score: Wis is the correct modifier. Please see the General Homebrew FAQ #6: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq).

I had to "wake up" the website for it to work.. I fr thought I did something wrong.

I figured that’s what it would be. I’m glad you got it working.

Thanks you've been really helpful

A year later, hit the same snag, and the 'wake up the character sheet' is what did it for me! Thanks!